Haploidisten

Haploidisten is a term encountered in genetics and biology to denote organisms, cells, or life stages that possess a single complete set of chromosomes (n). The word is formed from haploid and a suffix that denotes a state or association, and in some linguistic traditions it is used to refer to the haploid state itself or to organisms predominantly in that state. In biology, haploid individuals carry only one copy of each gene, so recessive traits are expressed directly.

Life cycles vary: many bacteria and some protists remain haploid for most of their existence. In plants, fungi and some algae, the haploid phase can be dominant or alternating with a diploid phase; sexual reproduction often produces haploid spores after meiosis. Unicellular yeasts such as Saccharomyces cerevisiae can exist as haploid or diploid forms, mating to form diploids that can sporulate back to haploids.

In research, haploidy facilitates genetic analysis because phenotypes map directly to genotypes. Haploid strains are widely employed in mutagenesis, functional genomics, and screening experiments. The concept of Haploidisten also appears in educational contexts as a label for the study or discussion of haploid biology in lectures, textbooks, or citizen science materials.

See also: haploid, ploidy, meiosis, mitosis, gametophyte, sporophyte.